1. Field of the Invention
The field of this invention relates to locking devices for telescopic members and more particularly to a locking device which can be quickly and easily manually manipulated to unlock the telescopic members to permit longitudinal sliding movement therebetween.
2. Description of the Prior Art
Telescopic tubes are in exceedingly common use. Telescopic tubes are commonly used on tripods with these tripods being used in conjunction with cameras, telescopes, lighting equipment, surveying equipment, and so forth. Other usages for telescopic tubes are outer space structures, tent poles, music stands, scaffolding, microphone stands, antennas, table legs, and so forth.
The main purpose for using telescopic tubes is to permit the overall structure to collapse to a smaller configuration generally facilitating portability. When the telescopic tubes are extended, the device can assume a relatively long length to fit the length requirements of the various uses to which the instruments are to be put. In addition, in conjunction with photographic tripods and surveying equipment, it is common to increase or decrease the length of a telescopic tube arrangement for the purpose of achieving a particular positioning of the camera or the surveying tool. At times, this adjustment has to be exceedingly precise, especially in conjunction with surveying equipment. The surveying equipment may be used on uneven terrain and the different legs of the telescopic tubes varied in their lengths so as to locate the surveying tool at a precisely level position.
Within the prior art, to change the position of a pair of telescopic tubes, these tubes are provided with a coupling interconnecting the tubes. This coupling is to be tightened to secure together the tubes and then must be loosened to permit adjusting of the tubes. Such couplings typically employ threaded elements which are rotated in one direction for tightening and rotated in the opposite direction for loosening. Operation of these threaded elements proves to be cumbersome and time consuming, especially in situations where a quick adjustment of the telescopic tubes is required. Also, lever activated camming devices are commonly used also requiring multiple steps to achieve adjustment and locking.